1. Field of the Invention
The present invention relates to a waterproof connector having a wire insertion part characterized by a waterproof structure resulting from ultrasonic oscillation.
2. Description of the Related Art
Japanese Unexamined Patent Publication (kokai) No. 9-320651 discloses one conventional waterproof structure for the connector. In the publication, there are shown covered wires each having a conductor covered with a synthetic covering part. In this structure, a pair of upper and lower resinous tips are used for a part of the structure where two covered wires intersect with each other.
The lower resinous tip is provided, at a center portion thereof, with a projecting welding boss and also provided, at the four corners, with guide grooves into which the covered wires are accommodated. Each guide groove has a cover removing part and a waterproof groove part, which are formed along a direction extending from the welding boss toward the outside, in order There is remained a gap defined between each guide groove and the welding boss.
Similarly to the lower resinous tip, the upper resinous tip has a welding boss formed to project at the center portion and four guide grooves formed on four corners to define gaps between each guide groove and the welding boss. Also in each guide groove, a cover removing part and a waterproof groove part are formed in order.
According to the above-mentioned structure, on condition of setting the lower resinous tip in an amble, the covered wires are inserted into the guide grooves of the lower resinous tip so as to intersect with each other and sequentially, the upper resinous tip is turned over and abutted on the lower resinous tip. This abutment allows both welding bosses of the upper and lower tips to mutually contact with each other and also causes the covered wires to be interposed between the guide grooves. In this state, the resultant assembly is subjected to the ultrasonic oscillation by an ultrasonic horn exerting pressure on the upper tip.
Consequently, the cover parts of the covered wires are molten to enter into the waterproof grooves, so that both conductors are exposed and connected with each other. The further continuation of ultrasonic oscillating under pressure allows both of the welding bosses to be molten and welded to each other. In this state, the waterproof grooves are filled up with the molten resinous material forming the insulating cover parts. Thereafter, as time goes by, the molten material of the cover parts is hardened while fulfilling the waterproof grooves in the form of a ring, whereby the connection having the waterproof characteristic can be provided between the intersecting covered wires.
Because of its effectiveness in the covered wires, the availability of the above-mentioned waterproof structure to a connector which accommodates terminals connected to the wires would make it to be a waterproof connector. In this case, it is executed to engage each terminal doubly in order to prevent it from withdrawing from the connector certainly.
The availability to the connector is carried out in accordance with the following steps of:
1 inserting each covered wire into each terminal and connecting the former with the latter by the terminal's crimping etc.;
2 accommodating the terminal having the covered wire connected thereto in a housing of the connector and engaging the terminal with an engagement lance;
3 sequentially subjecting the covered wire extending from the rear end of each terminal to the ultrasonic oscillation under pressure thereby to melt the insulating cover part of the covered wire for the resultant waterproof structure; and
4 engaging the terminal with double engagement members for fall-stop after the step of 3.
On the contrary, the double engagement operation of the terminal, which has been adopted up to now, comprises the steps of:
1 connecting each covered wire to each terminal;
2 accommodating the terminal in the housing and engaging it therein; and
3 engaging the terminal in the housing doubly.
That is, the former operation for the above-mentioned waterproof structure has a large number of steps in comparison with the number of steps in the latter operation, by the waterproofing. Furthermore, the former operation requires the double engagement members for the double engagement, increasing the number of components.